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3.1 DESCRIPTION
3 HARDWARE
3.1.7 CONTACT INPUTS / OUTPUTS
3
Figure 3–7: CONTACT INPUTS CONNECTIONS
Wet contacts must be connected to the inputs of the relay. A wet contact has one side connected to the positive terminal of
an external DC power supply. The other side of this contact is connected to the required contact input terminal (A8 or A9).
In addition, the negative side of the external source must be connected to the relay common (negative) terminal (A10). The
maximum external voltage source voltage for this arrangement is 300 Vdc for HI models and 57.6 for LO models.
The voltage threshold at which an input will detect a closed contact input depends on the relay model. For low voltage
range relays (LO model), the threshold is set to 12 Vdc. For high voltage range relays (HI model), the voltage threshold is
75 Vdc.
In case of using AC voltage, it must be ensured that there is no voltage (less than 10 Vac) between the input common
terminal, A10, and the ground terminal. The AC system must be line/neutral type, and not line/line, ensuring that the neutral
and ground do not differ in more than 10 Vac. The reason for this is that there might be enough current circulating through
the EMC filtering capacitors on these inputs to cause undesired activation.
If it is not possible to ensure the previous conditions, the connection shown below can be used, where lines are wired only
to inputs (A8 and A9), and the common (A10) is connected to the unit ground terminal.
Figure 3–8: CONTACT INPUTS CONNECTIONS (AC ACTIVATION)
3-8
MIFII Digital Feeder Relay
GEK-106237P
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